Downlink channel design for lte with low latency

ABSTRACT

An example data structure for managing user equipment communications in a wireless communications system is presented, as well as methods and apparatuses configured to implement the data structure. For instance, the data structure may include a downlink subframe comprising two slots and including one or more quick downlink channels having a single-slot transmission time interval. In addition, the example data structure may include one or more resource element blocks each comprising one or more resource elements into which a frequency bandwidth is divided within one or both of the two slots, wherein each of the one or more resource element blocks comprises a control channel region or a data channel region. Furthermore, the example data structure may include one or more resource grants, located within one or more control channel regions, for one or more user equipment served by the one or more quick downlink channels.

CROSS-REFERENCE TO RELATED APPLICATION

The present Application for Patent is a Continuation Application of U.S.application Ser. No. 14/836,183, filed Aug. 26, 2015, entitled “DOWNLINKCHANNEL DESIGN FOR LTE WITH LOW LATENCY,” which claims priority toProvisional Application No. 62/056,347 entitled “DOWNLINK CHANNEL DESIGNFOR LTE WITH LOW LATENCY” filed Sep. 26, 2014, all of which are assignedto the assignee hereof and hereby expressly incorporated by referenceherein for all purposes.

BACKGROUND

The present disclosure relates generally to communication systems, andmore particularly, to a downlink frame structure and method of downlinktransmission for managing communications with one or more user equipment(UE) in a wireless communications system.

Wireless communications systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communications systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of such multiple-access technologies includecode division multiple access (CDMA) systems, time division multipleaccess (TDMA) systems, frequency division multiple access (FDMA)systems, orthogonal frequency division multiple access (OFDMA) systems,single-carrier frequency division multiple access (SC-FDMA) systems, andtime division synchronous code division multiple access (TD-SCDMA)systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example of an emergingtelecommunication standard is Long Term Evolution (LTE). LTE is a set ofenhancements to the Universal Mobile Telecommunications System (UMTS)mobile standard promulgated by Third Generation Partnership Project(3GPP). It is designed to better support mobile broadband Internetaccess by improving spectral efficiency, lower costs, improve services,make use of new spectrum, and better integrate with other open standardsusing OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), andmultiple-input multiple-output (MIMO) antenna technology. However, asthe demand for mobile broadband access continues to increase, thereexists a need for further improvements in LTE technology. Preferably,these improvements should be applicable to other multi-accesstechnologies and the telecommunication standards that employ thesetechnologies.

In wireless communications systems employing legacy LTE, a plurality ofUEs served by a particular eNodeB may receive data from the eNodeB overa shared downlink channel called the Physical Downlink Shared Channel(PDSCH). In addition, control information associated with the PDSCH ormay be transmitted to the UEs by the eNodeB via a Physical DownlinkControl Channel (PDCCH) and/or an Enhanced PDCCH (ePDCCH). The controlinformation included in the PDCCH or ePDCCH may include one or moreuplink or downlink resource element (RE) grants for an LTE subframe. Inlegacy LTE, each LTE subframe has a transmission time interval (TTI) of1 ms and is divided into two 0.5 ms slots. Any RE grants transmitted onthe PDCCH, however, are for a remaining duration of the entire subframe(i.e., the full remainder of 1 ms). As such, legacy LTE does not allowfor resource scheduling at a level of granularity less than a full 1 msLTE subframe, even if faster downlink communication rates are desiredfor a particular communication flow.

As such, improvements in the downlink frame structure and downlinktransmission methods are needed.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

In accordance with one or more aspects and corresponding disclosurethereof, various techniques are described in connection with exampledata structures, methods, and apparatuses for improving wirelesscommunication speed and reliability between one or more UEs and networkentities in wireless communication networks.

For instance, in an aspect of the present disclosure, an example datastructure for managing user equipment communications in a wirelesscommunications system is described. The example data structure mayinclude a downlink subframe comprising two slots and including one ormore quick downlink channels having a single-slot TTI. Additionally, theexample data structure may include one or more resource element blockseach comprising one or more resource elements into which a frequencybandwidth is divided within one or both of the two slots, wherein eachof the one or more resource element blocks comprises a control channelregion or a data channel region. Furthermore, the example data structuremay include one or more resource grants, located within one or morecontrol channel regions, for one or more user equipment served by theone or more quick downlink channels.

In a further aspect, the present disclosure presents an example methodof managing UE communications in a wireless communications system, andmay include obtaining, at a network entity, user data for transmissionto one or more user equipment UEs on a downlink channel. The examplemethod may further include determining one or more delivery constraintsassociated with at least one of the user data and the one or more UEs.Moreover, the example method may include generating, based on the userdata for transmission and the one or more delivery constraints, adownlink subframe data structure for allocating downlink channelresources for transmission of the user data for transmission. In theexample method, the downlink subframe data structure may include adownlink subframe comprising two slots and including one or more quickdownlink channels having a single-slot TTI. Furthermore, the exampledownlink subframe data structure may further include one or moreresource element blocks each comprising one or more resource elementsinto which a frequency bandwidth is divided within one or both of thetwo slots, wherein each of the one or more resource element blockscomprises a control channel region or a data channel region and one ormore resource grants, located within one or more control channelregions, for the one or more UEs served by the one or more quickdownlink channels.

Moreover, the present disclosure describes an example apparatus formanaging UE communications in a wireless communications system, and mayinclude means for obtaining, at a network entity, user data fortransmission to one or more user equipment UEs on a downlink channel.The example apparatus may further include means for determining one ormore delivery constraints associated with at least one of the user dataand the one or more UEs. Moreover, the example apparatus may includemeans for generating, based on the user data for transmission and theone or more delivery constraints, a downlink subframe data structure forallocating downlink channel resources for transmission of the user datafor transmission. In the example apparatus, the downlink subframe datastructure may include a downlink subframe comprising two slots andincluding one or more quick downlink channels having a single-slot TTI.Furthermore, the example downlink subframe data structure may furtherinclude one or more resource element blocks each comprising one or moreresource elements into which a frequency bandwidth is divided within oneor both of the two slots, wherein each of the one or more resourceelement blocks comprises a control channel region or a data channelregion and one or more resource grants, located within one or morecontrol channel regions, for the one or more UEs served by the one ormore quick downlink channels.

In an additional aspect, an example apparatus for managing UEcommunications in a wireless communications system is presented, whichmay include a processor and a memory coupled to the processor. In someexamples, the memory may store processor-executable instructions, thatwhen executed by the processor, cause the processor to obtain, at anetwork entity, user data for transmission to one or more UEs on adownlink channel. Additionally, the memory may storeprocessor-executable instructions, that when executed by the processor,cause the processor to determine one or more delivery constraintsassociated with at least one of the user data and the one or more UEs.In addition, the memory may store processor-executable instructions,that when executed by the processor, cause the processor to generate,based on the user data for transmission and the one or more deliveryconstraints, a downlink subframe data structure for allocating downlinkchannel resources for transmission of the user data for transmission.According to the example apparatus, the downlink subframe data structuremay include a downlink subframe comprising two slots and including oneor more quick downlink channels having a single-slot TTI. In addition,the downlink subframe data structure may include one or more resourceelement blocks each comprising one or more resource elements into whicha frequency bandwidth is divided within one or both of the two slots,wherein each of the one or more resource element blocks comprises acontrol channel region or a data channel region. Furthermore, thedownlink subframe data structure may include one or more resourcegrants, located within one or more control channel regions, for the oneor more UEs served by the one or more quick downlink channels.

Moreover, the disclosure presents an example computer-readable mediumstoring computer-executable code for managing UE communications in awireless communications system. In an aspect, the computer-executablecode may include code for obtaining, at a network entity, user data fortransmission to one or more user equipment UEs on a downlink channel. Inaddition, the computer-executable code may include code for determiningone or more delivery constraints associated with at least one of theuser data and the one or more UEs. Furthermore, the computer-executablecode may include code for generating, based on the user data fortransmission and the one or more delivery constraints, a downlinksubframe data structure for allocating downlink channel resources fortransmission of the user data for transmission. According to the examplecomputer-readable medium, the downlink subframe data structure mayinclude a downlink subframe comprising two slots and including one ormore quick downlink channels having a single-slot TTI. The downlinksubframe data structure may also include one or more resource elementblocks each comprising one or more resource elements into which afrequency bandwidth is divided within one or both of the two slots,wherein each of the one or more resource element blocks comprises acontrol channel region or a data channel region. Additionally, thedownlink subframe data structure may include one or more resourcegrants, located within one or more control channel regions, for the oneor more UEs served by the one or more quick downlink channels.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram conceptually illustrating an example of atelecommunications system, in accordance with an aspect of the presentdisclosure;

FIG. 2 is a diagram illustrating an example of an access network;

FIG. 3 is a diagram illustrating an example of a DL frame structure inLTE;

FIG. 4 is a diagram illustrating an example of an UL frame structure inLTE;

FIG. 5 is a diagram illustrating an example of a radio protocolarchitecture for the user and control planes;

FIG. 6 is a diagram illustrating an example of an evolved Node B anduser equipment in an access network;

FIG. 7 is a diagram illustrating an example data structure for downlinkresource element block allocation according to the present disclosure;

FIG. 8 is a diagram illustrating a downlink scheduling componentconfigured to implement aspects of the present disclosure;

FIG. 9 is a flow chart of a method of wireless communication;

FIG. 10 is a conceptual data flow diagram illustrating the data flowbetween different modules/means/components in an exemplary apparatus;

FIG. 11 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system;

FIG. 12 is a flow chart of a method of wireless communication;

FIG. 13 is a conceptual data flow diagram illustrating the data flowbetween different modules/means/components in an exemplary apparatus;and

FIG. 14 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, modules, components,circuits, steps, processes, algorithms, etc. (collectively referred toas “elements”). These elements may be implemented using electronichardware, computer software, or any combination thereof. Whether suchelements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented with a “processing system”that includes one or more processors. Examples of processors includemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate arrays (FPGAs), programmable logic devices(PLDs), state machines, gated logic, discrete hardware circuits, andother suitable hardware configured to perform the various functionalitydescribed throughout this disclosure. One or more processors in theprocessing system may execute software. Software shall be construedbroadly to mean instructions, instruction sets, code, code segments,program code, programs, subprograms, software modules, applications,software applications, software packages, routines, subroutines,objects, executables, threads of execution, procedures, functions, etc.,whether referred to as software, firmware, middleware, microcode,hardware description language, or otherwise.

Accordingly, in one or more aspects, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes computer storage media. Storage mediamay be any available media that can be accessed by a computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code in the form ofinstructions or data structures and that can be accessed by a computer.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), and floppy disk where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

The present disclosure presents example data structures and transmissionmethods for managing downlink communications to one or more UEs, and inparticular, to reduce latency as compared to legacy downlink datastructures and downlink transmission methods. These data structures ofthe present disclosure may include one or more resource element blocksinto which a frequency bandwidth of one or more downlink channels isdivided within a slot of an LTE subframe. Likewise, any REs of thesubframe may have an assignment that lasts for a single slot in thesubframe or for the entire subframe.

In addition, any of the resource element blocks of a particular slot maycomprise a control channel region or a data channel region. A controlchannel region may include one or more resource grants associated withone or more UEs served by a network entity (e.g., an eNodeB). Suchresource grants may include one or more downlink resource grants and/orone or more uplink resource grants. For example, in one aspect of thepresent disclosure, a control channel region located in the first symbol(or first few symbols) of a subframe may be utilized for schedulingdownlink frequency grants in data channel region that comprises theremainder of the first slot of the subframe or for the remainder of theentire subframe. For purposes of the present disclosure, the controlchannel corresponding to such a control channel region may be referredto as a Quick Physical Downlink Control Channel (QPDCCH).

In another aspect of the present disclosure, a control channel regionmay include a resource element block spanning an entire single slot (ora portion thereof) and may be utilized for scheduling downlink frequencygrants for one or more other resource element blocks in the same slot.For purposes of the present disclosure, the control channelcorresponding to such a control channel region may be referred to as aQuick Enhanced Physical Downlink Control Channel (QEPDCCH).

Furthermore, a data channel region of the present disclosure may includea resource element block spanning an entire single slot (or a portionthereof) during which user data is transmitted to a UE receiving adownlink grant in a control channel region (e.g., corresponding to aQPDCCH or a QEPDCCH). For purposes of the present disclosure, the datachannel corresponding to such a data channel region may be referred toas a Quick Physical Downlink Shared Channel (QPDSCH).

Additionally, for purposes of the present disclosure, any channel thatmay have a temporal length (e.g., TTI) of a single slot (or a portion ofa single slot) or includes resource grants for a data channel having atemporal length of a single slot (or a portion of a single slot) may bereferred to herein as a “Quick LTE channel.” These Quick LTE channelsmay include, in a non-limiting aspect, a QPDCCH, a QEPDCCH, and aQPDSCH. Furthermore, any reference to “Quick LTE” in the presentdisclosure may refer to a data structure for resource element scheduling(or a method or apparatus implementing the data structure) having one ormore channels or resource element blocks that are or can be allocated,assigned, or divided on a per-slot basis and/or have a TTI of 0.5ms.Such references to Quick LTE may include “Quick LTE scheduling,” “QuickLTE scheme,” or the like.

Moreover, the example data structures of the present disclosure areconfigured to additionally implement frame scheduling of legacy LTEchannels (e.g., PDCCH, EPDCCH, PDSCH) alongside the slot-specific REallocation aspects introduced by the present disclosure forcorresponding Quick LTE channels (e.g., QPDCCH, QEPDCCH, QPDSCH). Inthis way, the data structures described herein may be implemented forUEs or specific UE applications that are configured to utilize Quick LTEscheduling (per-slot scheduling) and/or legacy LTE scheduling(per-subframe scheduling). As the Quick LTE scheduling methods describedherein may utilize a 0.5 ms TTI rather than the 1 ms TTI of legacy LTE,these methods may increase communication rates two-fold and may cut around-trip time (RTT) associated with legacy LTE hybrid automatic repeatrequest (HARD) procedures in half (e.g., from 8 ms to 4 ms or less).

In an additional aspect of the present disclosure, a network entity(e.g., an eNodeB) is presented, which may be configured to managedownlink scheduling by generating one or more of the data structuresdisclosed herein. Furthermore, the network entity may be configured toobtain data for transmission to one or more UEs and may schedule thetransmission of the data using the data structure based on the dataand/or delivery constraints associated with the one or more UEs.

Referring first to FIG. 1, a diagram illustrates an example of awireless communications system 100, in accordance with an aspect of thepresent disclosure. The wireless communications system 100 includes aplurality of access points (e.g., base stations, eNBs, or WLAN accesspoints) 105, a number of user equipment (UEs) 115, and a core network130. Access points 105 may include a downlink scheduling component 602configured to expedite communication of control information and userdata with the number of UEs 115 using an Quick LTE data structure, forexample but not limited to data structure 700 of FIG. 7, below, whichmay include a TTI of one slot for some RE blocks. For example, the QuickLTE data structure may include one or more resource element blocks forallocating a PDCCH, EPDCCH, PDSCH, QPDCCH, QEPDCCH, and/or QPDSCH.Similarly, one or more of UEs 115 may include a downlink managementcomponent 661 configured to receive, decode and operate using the datastructure. Some of the access points 105 may communicate with the UEs115 under the control of a base station controller (not shown), whichmay be part of the core network 130 or the certain access points 105(e.g., base stations or eNBs) in various examples. Access points 105 maycommunicate control information and/or user data with the core network130 through backhaul links 132. In examples, the access points 105 maycommunicate, either directly or indirectly, with each other overbackhaul links 134, which may be wired or wireless communication links.The wireless communications system 100 may support operation on multiplecarriers (waveform signals of different frequencies). Multi-carriertransmitters can transmit modulated signals simultaneously on themultiple carriers. For example, each communication link 125 may be amulti-carrier signal modulated according to the various radiotechnologies described above. Each modulated signal may be sent on adifferent carrier and may carry control information (e.g., referencesignals, control channels, etc.), overhead information, data, etc.

In some examples, at least a portion of the wireless communicationssystem 100 may be configured to operate on multiple hierarchical layersin which one or more of the UEs 115 and one or more of the access points105 may be configured to support transmissions on a hierarchical layerthat has a reduced latency with respect to another hierarchical layer.In some examples a hybrid UE 115-a may communicate with access point105-a on both a first hierarchical layer that supports first layertransmissions with a first subframe type and a second hierarchical layerthat supports second layer transmissions with a second subframe type.For example, access point 105-a may transmit subframes of the secondsubframe type that are time division duplexed with subframes of thefirst subframe type.

In some examples, hybrid UE 115-a may acknowledge receipt of atransmission by providing ACK/NACK for the transmission through, forexample, a HARQ scheme. Acknowledgments from hybrid UE 115-a fortransmissions in the first hierarchical layer may be provided, in someexamples, after a predefined number of subframes following the subframein which the transmission was received. The hybrid UE 115-a, whenoperating in the second hierarchical layer may, in examples, acknowledgereceipt in a same subframe as the subframe in which the transmission wasreceived. The time required to transmit an ACK/NACK and receive aretransmission may be referred to as round trip time (RTT), and thussubframes of the second subframe type may have a second RTT that isshorter than a RTT for subframes of the first subframe type.

In other examples, a second layer UE 115-b may communicate with accesspoint 105-b on the second hierarchical layer only. Thus, hybrid UE 115-aand second layer UE 115-b may belong to a second class of UEs 115 thatmay communicate on the second hierarchical layer, while legacy UEs 115may belong to a first class of UEs 115 that may communicate on the firsthierarchical layer only. Access point 105-b and UE 115-b may communicateon the second hierarchical layer through transmissions of subframes ofthe second subframe type. Access point 105-b may transmit subframes ofthe second subframe type exclusively, or may transmit one or moresubframes of the first subframe type on the first hierarchical layerthat are time division multiplexed with subframes of the second subframetype. Second layer UE 115-b, in the event that access point 105-btransmits subframes of the first subframe type, may ignore suchsubframes of the first subframe type. Thus, second layer UE 115-b mayacknowledge receipt of transmissions in a same subframe as the subframein which the transmissions are received. Thus, second layer UE 115-b mayoperate with reduced latency compared to UEs 115 that operate on thefirst hierarchical layer.

The access points 105 may wirelessly communicate with the UEs 115 viaone or more access point antennas. Each of the access points 105 sitesmay provide communication coverage for a respective coverage area 110.In some examples, access points 105 may be referred to as a basetransceiver station, a radio base station, a radio transceiver, a basicservice set (BSS), an extended service set (ESS), a NodeB, eNodeB, HomeNodeB, a Home eNodeB, or some other suitable terminology. The coveragearea 110 for a base station may be divided into sectors making up only aportion of the coverage area (not shown). The wireless communicationssystem 100 may include access points 105 of different types (e.g.,macro, micro, and/or pico base stations). The access points 105 may alsoutilize different radio technologies, such as cellular and/or WLAN radioaccess technologies. The access points 105 may be associated with thesame or different access networks or operator deployments. The coverageareas of different access points 105, including the coverage areas ofthe same or different types of access points 105, utilizing the same ordifferent radio technologies, and/or belonging to the same or differentaccess networks, may overlap.

In LTE/LTE-A network communication systems, the terms evolved Node B(eNodeB or eNB) may be generally used to describe the access points 105.The wireless communications system 100 may be a HeterogeneousLTE/LTE-A/ULL LTE network in which different types of access pointsprovide coverage for various geographical regions. For example, eachaccess point 105 may provide communication coverage for a macro cell, apico cell, a femto cell, and/or other types of cell. Small cells such aspico cells, femto cells, and/or other types of cells may include lowpower nodes or LPNs. A macro cell generally covers a relatively largegeographic area (e.g., several kilometers in radius) and may allowunrestricted access by UEs 115 with service subscriptions with thenetwork provider. A small cell would generally cover a relativelysmaller geographic area and may allow unrestricted access by UEs 115with service subscriptions with the network provider, for example, andin addition to unrestricted access, may also provide restricted accessby UEs 115 having an association with the small cell (e.g., UEs in aclosed subscriber group (CSG), UEs for users in the home, and the like).An eNB for a macro cell may be referred to as a macro eNB. An eNB for asmall cell may be referred to as a small cell eNB. An eNB may supportone or multiple (e.g., two, three, four, and the like) cells.

The core network 130 may communicate with the eNBs or other accesspoints 105 via a backhaul 132 (e.g., 51 interface, etc.). The accesspoints 105 may also communicate with one another, e.g., directly orindirectly via backhaul links 134 (e.g., X2 interface, etc.) and/or viabackhaul links 132 (e.g., through core network 130). The wirelesscommunications system 100 may support synchronous or asynchronousoperation. For synchronous operation, the access points 105 may havesimilar frame timing, and transmissions from different access points 105may be approximately aligned in time. For asynchronous operation, theaccess points 105 may have different frame timing, and transmissionsfrom different access points 105 may not be aligned in time.Furthermore, transmissions in the first hierarchical layer and secondhierarchical layer may or may not be synchronized among access points105. The techniques described herein may be used for either synchronousor asynchronous operations.

The UEs 115 are dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to by those skilled in the art as a mobile station, asubscriber station, a mobile unit, a subscriber unit, a wireless unit, aremote unit, a mobile device, a wireless device, a wirelesscommunications device, a remote device, a mobile subscriber station, anaccess terminal, a mobile terminal, a wireless terminal, a remoteterminal, a handset, a user agent, a mobile client, a client, or someother suitable terminology. A UE 115 may be a cellular phone, a personaldigital assistant (PDA), a wireless modem, a wireless communicationdevice, a handheld device, a tablet computer, a laptop computer, acordless phone, a wearable item such as a watch or glasses, a wirelesslocal loop (WLL) station, or the like. A UE 115 may be able tocommunicate with macro eNodeBs, small cell eNodeBs, relays, and thelike. A UE 115 may also be able to communicate over different accessnetworks, such as cellular or other WWAN access networks, or WLAN accessnetworks.

The communication links 125 shown in wireless communications system 100may include uplink (UL) transmissions from a UE 115 to an access point105, and/or downlink (DL) transmissions, from an access point 105 to aUE 115. The downlink transmissions may also be called forward linktransmissions while the uplink transmissions may also be called reverselink transmissions. The communication links 125 may carry transmissionsof each hierarchical layer which, in some examples, may be multiplexedin the communication links 125. The UEs 115 may be configured tocollaboratively communicate with multiple access points 105 through, forexample, Multiple Input Multiple Output (MIMO), carrier aggregation(CA), Coordinated Multi-Point (CoMP), or other schemes. MIMO techniquesuse multiple antennas on the access points 105 and/or multiple antennason the UEs 115 to transmit multiple data streams. Carrier aggregationmay utilize two or more component carriers on a same or differentserving cell for data transmission. CoMP may include techniques forcoordination of transmission and reception by a number of access points105 to improve overall transmission quality for UEs 115 as well asincreasing network and spectrum utilization.

As mentioned, in some examples access points 105 and UEs 115 may utilizecarrier aggregation to transmit on multiple carriers. In some examples,access points 105 and UEs 115 may concurrently transmit in a firsthierarchical layer, within a frame, one or more subframes each having afirst subframe type using two or more separate carriers. Each carriermay have a bandwidth of, for example, 20 MHz, although other bandwidthsmay be utilized. Hybrid UE 115-a, and/or second layer UE 115-b may, incertain examples, receive and/or transmit one or more subframes in asecond hierarchical layer utilizing a single carrier that has abandwidth greater than a bandwidth of one or more of the separatecarriers. For example, if four separate 20 MHz carriers are used in acarrier aggregation scheme in the first hierarchical layer, a single 80MHz carrier may be used in the second hierarchical layer. The 80 MHzcarrier may occupy a portion of the radio frequency spectrum that atleast partially overlaps the radio frequency spectrum used by one ormore of the four 20 MHz carriers. In some examples, scalable bandwidthfor the second hierarchical layer type may be combined techniques toprovide shorter RTTs such as described above, to provide furtherenhanced data rates.

Each of the different operating modes that may be employed by wirelesscommunications system 100 may operate according to frequency divisionduplexing (FDD) or time division duplexing (TDD). In some examples,different hierarchical layers may operate according to different TDD orFDD modes. For example, a first hierarchical layer may operate accordingto FDD while a second hierarchical layer may operate according to TDD.In some examples, OFDMA communications signals may be used in thecommunication links 125 for LTE downlink transmissions for eachhierarchical layer, while single carrier frequency division multipleaccess (SC-FDMA) communications signals may be used in the communicationlinks 125 for LTE uplink transmissions in each hierarchical layer.Additional details regarding implementation of hierarchical layers in asystem such as the wireless communications system 100, as well as otherfeatures and functions related to communications in such systems, areprovided below with reference to the following figures.

FIG. 2 is a diagram illustrating an example of an access network 200 inan LTE network architecture. In this example, the access network 200 isdivided into a number of cellular regions (cells) 202. One or more lowerpower class eNBs 208 may have cellular regions 210 that overlap with oneor more of the cells 202. The lower power class eNB 208 may be a femtocell (e.g., home eNB (HeNB)), pico cell, micro cell, or remote radiohead (RRH). The macro eNBs 204 are each assigned to a respective cell202 and are configured to provide an access point to the Evolved PacketCore for all the UEs 115 (see FIG. 1) in the cells 202. In an aspect,eNBs 204 may constitute an access point 105 of FIG. 1 and may include adownlink scheduling component 602 configured to expedite communicationof control information and user data with the number of UEs 115 using anQuick LTE data structure, for example but not limited to data structure700 of FIG. 7, which may include a TTI of one slot for some RE blocks.Similarly, one or more of UEs 115 may include a downlink managementcomponent 661 configured to receive, decode and operate using the datastructure. There is no centralized controller in this example of anaccess network 200, but a centralized controller may be used inalternative configurations. The eNBs 204 are responsible for all radiorelated functions including radio bearer control, admission control,mobility control, scheduling, security, and connectivity to the servinggateway 116.

The modulation and multiple access scheme employed by the access network200 may vary depending on the particular telecommunications standardbeing deployed. In LTE applications, OFDM is used on the DL and SC-FDMAis used on the UL to support both frequency division duplexing (FDD) andtime division duplexing (TDD). As those skilled in the art will readilyappreciate from the detailed description to follow, the various conceptspresented herein are well suited for LTE applications. However, theseconcepts may be readily extended to other telecommunication standardsemploying other modulation and multiple access techniques. By way ofexample, these concepts may be extended to Evolution-Data Optimized(EV-DO) or Ultra Mobile Broadband (UMB). EV-DO and UMB are air interfacestandards promulgated by the 3rd Generation Partnership Project 2(3GPP2) as part of the CDMA2000 family of standards and employs CDMA toprovide broadband Internet access to mobile stations. These concepts mayalso be extended to Universal Terrestrial Radio Access (UTRA) employingWideband-CDMA (W-CDMA) and other variants of CDMA, such as TD-SCDMA;Global System for Mobile Communications (GSM) employing TDMA; andEvolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, and Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE and GSMare described in documents from the 3GPP organization. CDMA2000 and UMBare described in documents from the 3GPP2 organization. The actualwireless communication standard and the multiple access technologyemployed will depend on the specific application and the overall designconstraints imposed on the system.

The eNBs 204 may have multiple antennas supporting MIMO technology. Theuse of MIMO technology enables the eNBs 204 to exploit the spatialdomain to support spatial multiplexing, beamforming, and transmitdiversity. Spatial multiplexing may be used to transmit differentstreams of data simultaneously on the same frequency. The data steamsmay be transmitted to a single UE 115 to increase the data rate or tomultiple UEs 115 to increase the overall system capacity. This isachieved by spatially precoding each data stream (i.e., applying ascaling of an amplitude and a phase) and then transmitting eachspatially precoded stream through multiple transmit antennas on the DL.The spatially precoded data streams arrive at the UE(s) 115 withdifferent spatial signatures, which enables each of the UE(s) 115 torecover the one or more data streams destined for that UE 115. On theUL, each UE 115 transmits a spatially precoded data stream, whichenables the eNB 204 to identify the source of each spatially precodeddata stream.

Spatial multiplexing is generally used when channel conditions are good.When channel conditions are less favorable, beamforming may be used tofocus the transmission energy in one or more directions. This may beachieved by spatially precoding the data for transmission throughmultiple antennas. To achieve good coverage at the edges of the cell, asingle stream beamforming transmission may be used in combination withtransmit diversity.

In the detailed description that follows, various aspects of an accessnetwork will be described with reference to a MIMO system supportingOFDM on the DL. OFDM is a spread-spectrum technique that modulates dataover a number of subcarriers within an OFDM symbol. The subcarriers arespaced apart at precise frequencies. The spacing provides“orthogonality” that enables a receiver to recover the data from thesubcarriers. In the time domain, a guard interval (e.g., cyclic prefix)may be added to each OFDM symbol to combat inter-OFDM-symbolinterference. The UL may use SC-FDMA in the form of a DFT-spread OFDMsignal to compensate for high peak-to-average power ratio (PAPR).

FIG. 3 is a diagram 300 illustrating an example of a DL frame structurein LTE, which, in some examples, may be utilized in conjunction with thedownlink frame structure provided by the present disclosure. A frame (10ms) may be divided into 10 equally sized sub-frames. Each sub-frame mayinclude two consecutive time slots. A resource grid may be used torepresent two time slots, each time slot including a resource elementblock. The resource grid is divided into multiple resource elements. InLTE, a resource element block may contain 12 consecutive subcarriers inthe frequency domain and, for a normal cyclic prefix in each OFDMsymbol, 7 consecutive OFDM symbols in the time domain, or 84 resourceelements. For an extended cyclic prefix, a resource element block maycontain 6 consecutive OFDM symbols in the time domain and has 72resource elements. Some of the resource elements, as indicated as R 302,304, include DL reference signals (DL-RS). The DL-RS includeCell-specific RS (CRS) (also sometimes called common RS) 302 andUE-specific RS (UE-RS) 304. UE-RS 304 are transmitted only on theresource element blocks upon which the corresponding PDSCH is mapped.The number of bits carried by each resource element depends on themodulation scheme. Thus, the more resource element blocks that a UEreceives and the higher the modulation scheme, the higher the data ratefor the UE.

FIG. 4 is a diagram 400 illustrating an example of an UL frame structurein LTE. The available resource element blocks for the UL may bepartitioned into a data section and a control section. The controlsection may be formed at the two edges of the system bandwidth and mayhave a configurable size. The resource element blocks in the controlsection may be assigned to UEs for transmission of control information.The data section may include all resource element blocks not included inthe control section. The UL frame structure results in the data sectionincluding contiguous subcarriers, which may allow a single UE to beassigned all of the contiguous subcarriers in the data section.

A UE may be assigned resource element blocks 410 a, 410 b in the controlsection to transmit control information to an eNB. The UE may also beassigned resource element blocks 420 a, 420 b in the data section totransmit data to the eNB. The UE may transmit control information in aphysical UL control channel (PUCCH) on the assigned resource elementblocks in the control section. The UE may transmit only data or bothdata and control information in a physical UL shared channel (PUSCH) onthe assigned resource element blocks in the data section. A ULtransmission may span both slots of a subframe and may hop acrossfrequency.

A set of resource element blocks may be used to perform initial systemaccess and achieve UL synchronization in a physical random accesschannel (PRACH) 430. The PRACH 430 carries a random sequence and cannotcarry any UL data/signaling. Each random access preamble occupies abandwidth corresponding to six consecutive resource element blocks. Thestarting frequency is specified by the network. That is, thetransmission of the random access preamble is restricted to certain timeand frequency resources. There is no frequency hopping for the PRACH.The PRACH attempt is carried in a single subframe (1 ms) or in asequence of few contiguous subframes and a UE can make only a singlePRACH attempt per frame (10 ms).

FIG. 5 is a diagram 500 illustrating an example of a radio protocolarchitecture for the user and control planes in LTE. The radio protocolarchitecture for the UE and the eNB is shown with three layers: Layer 1,Layer 2, and Layer 3. Layer 1 (L1 layer) is the lowest layer andimplements various physical layer signal processing functions. The L1layer will be referred to herein as the physical layer 506. Layer 2 (L2layer) 508 is above the physical layer 506 and is responsible for thelink between the UE and eNB over the physical layer 506.

In the user plane, the L2 layer 508 includes a media access control(MAC) sublayer 510, a radio link control (RLC) sublayer 512, and apacket data convergence protocol (PDCP) 514 sublayer, which areterminated at the eNB on the network side. Although not shown, the UEmay have several upper layers above the L2 layer 508 including a networklayer (e.g., IP layer) that is terminated at the PDN gateway 118 on thenetwork side, and an application layer that is terminated at the otherend of the connection (e.g., far end UE, server, etc.).

The PDCP sublayer 514 provides multiplexing between different radiobearers and logical channels. The PDCP sublayer 514 also provides headercompression for upper layer data packets to reduce radio transmissionoverhead, security by ciphering the data packets, and handover supportfor UEs between eNBs. The RLC sublayer 512 provides segmentation andreassembly of upper layer data packets, retransmission of lost datapackets, and reordering of data packets to compensate for out-of-orderreception due to hybrid automatic repeat request (HARD). The MACsublayer 510 provides multiplexing between logical and transportchannels. The MAC sublayer 510 is also responsible for allocating thevarious radio resources (e.g., resource element blocks) in one cellamong the UEs. The MAC sublayer 510 is also responsible for HARQoperations.

In the control plane, the radio protocol architecture for the UE and eNBis substantially the same for the physical layer 506 and the L2 layer508 with the exception that there is no header compression function forthe control plane. The control plane also includes a radio resourcecontrol (RRC) sublayer 516 in Layer 3 (L3 layer). The RRC sublayer 516is responsible for obtaining radio resources (i.e., radio bearers) andfor configuring the lower layers using RRC signaling between the eNB andthe UE.

FIG. 6 is a block diagram of an eNB 610 in communication with a UE 650in an access network. In the DL, upper layer packets from the corenetwork are provided to a controller/processor 675. Thecontroller/processor 675 implements the functionality of the L2 layer.In the DL, the controller/processor 675 provides header compression,ciphering, packet segmentation and reordering, multiplexing betweenlogical and transport channels, and radio resource allocations to the UE650 based on various priority metrics. The controller/processor 675 isalso responsible for HARQ operations, retransmission of lost packets,and signaling to the UE 650.

The transmit (TX) processor 616 implements various signal processingfunctions for the L1 layer (i.e., physical layer). The signal processingfunctions includes coding and interleaving to facilitate forward errorcorrection (FEC) at the UE 650 and mapping to signal constellationsbased on various modulation schemes (e.g., binary phase-shift keying(BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying(M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded andmodulated symbols are then split into parallel streams. Each stream isthen mapped to an OFDM subcarrier, multiplexed with a reference signal(e.g., pilot) in the time and/or frequency domain, and then combinedtogether using an Inverse Fast Fourier Transform (IFFT) to produce aphysical channel carrying a time domain OFDM symbol stream. The OFDMstream is spatially precoded to produce multiple spatial streams.Channel estimates from a channel estimator 674 may be used to determinethe coding and modulation scheme, as well as for spatial processing. Thechannel estimate may be derived from a reference signal and/or channelcondition feedback transmitted by the UE 650. Each spatial stream isthen provided to a different antenna 620 via a separate transmitter618TX. Each transmitter 618TX modulates an RF carrier with a respectivespatial stream for transmission. In addition, eNB 610 may include adownlink scheduling component 602 configured to expedite communicationof control information and user data with the number of UEs 115 using adata structure, for example but not limited to data structure 700 ofFIG. 7, which may include a TTI of one slot for some RE groups.

At the UE 650, each receiver 654RX receives a signal through itsrespective antenna 652. Each receiver 654RX recovers informationmodulated onto an RF carrier and provides the information to the receive(RX) processor 656. The RX processor 656 implements various signalprocessing functions of the L1 layer. The RX processor 656 performsspatial processing on the information to recover any spatial streamsdestined for the UE 650. If multiple spatial streams are destined forthe UE 650, they may be combined by the RX processor 656 into a singleOFDM symbol stream. The RX processor 656 then converts the OFDM symbolstream from the time-domain to the frequency domain using a Fast FourierTransform (FFT). The frequency domain signal comprises a separate OFDMsymbol stream for each subcarrier of the OFDM signal. The symbols oneach subcarrier, and the reference signal, is recovered and demodulatedby determining the most likely signal constellation points transmittedby the eNB 610. These soft decisions may be based on channel estimatescomputed by the channel estimator 658. The soft decisions are thendecoded and deinterleaved to recover the data and control signals thatwere originally transmitted by the eNB 610 on the physical channel. Thedata and control signals are then provided to the controller/processor659.

The controller/processor 659 implements the L2 layer. Thecontroller/processor can be associated with a memory 660 that storesprogram codes and data. The memory 660 may be referred to as acomputer-readable medium. In the UL, the controller/processor 659provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover upper layer packets from the core network. The upper layerpackets are then provided to a data sink 662, which represents all theprotocol layers above the L2 layer. Various control signals may also beprovided to the data sink 662 for L3 processing. Thecontroller/processor 659 is also responsible for error detection usingan acknowledgement (ACK) and/or negative acknowledgement (NACK) protocolto support HARQ operations. In addition, UE 650 may include a downlinkmanagement component 661 configured to receive, decode and operate usingthe data structure of the present disclosure.

In the UL, a data source 667 is used to provide upper layer packets tothe controller/processor 659. The data source 667 represents allprotocol layers above the L2 layer. Similar to the functionalitydescribed in connection with the DL transmission by the eNB 610, thecontroller/processor 659 implements the L2 layer for the user plane andthe control plane by providing header compression, ciphering, packetsegmentation and reordering, and multiplexing between logical andtransport channels based on radio resource allocations by the eNB 610.The controller/processor 659 is also responsible for HARQ operations,retransmission of lost packets, and signaling to the eNB 610.

Channel estimates derived by a channel estimator 658 from a referencesignal or feedback transmitted by the eNB 610 may be used by the TXprocessor 668 to select the appropriate coding and modulation schemes,and to facilitate spatial processing. The spatial streams generated bythe TX processor 668 are provided to different antenna 652 via separatetransmitters 654TX. Each transmitter 654TX modulates an RF carrier witha respective spatial stream for transmission.

The UL transmission is processed at the eNB 610 in a manner similar tothat described in connection with the receiver function at the UE 650.Each receiver 618RX receives a signal through its respective antenna620. Each receiver 618RX recovers information modulated onto an RFcarrier and provides the information to a RX processor 670. The RXprocessor 670 may implement the L1 layer.

The controller/processor 675 implements the L2 layer. Thecontroller/processor 675 can be associated with a memory 676 that storesprogram codes and data. The memory 676 may be referred to as acomputer-readable medium. In the UL, the controller/processor 675provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover upper layer packets from the UE 650. Upper layer packets fromthe controller/processor 675 may be provided to the core network. Thecontroller/processor 675 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations. In addition,controller/processor may be in communication with a

FIG. 7 is a diagram illustrating a non-limiting example of a datastructure 700 for managing expedited UE communications in a wirelesscommunications system. In an aspect, data structure 700 includes framescheduling for an example LTE subframe, which is divided in the timedomain (horizontally) into two slots (slot 0 702 and slot 1 704) and 14symbols (symbols 0-13). Furthermore, the temporal duration (horizontalaxis) of some resource element blocks of data structure 700 may be oneslot (0.5 ms TTI), whereas other resource element blocks may have atemporal duration of both slots (1 ms TTI). As such, by incorporatingcontrol and data channel resource element blocks having a TTI of oneslot (0.5 ms), data structure 700 allows for lower latency for downlinkdata transmissions relative to, for example, resource element blocks oflegacy LTE downlink data structures, which have a mandated downlink dataresource element block TTI of one subframe (1 ms). Furthermore, datastructure 700 provides for inter-operability with these existing legacyLTE data structures by allowing PDCCH, EPDCCH, and PDSCH resourceelement blocks to be scheduled along with the single-slot resourceelement blocks introduced by the present disclosure.

In an aspect of the present disclosure, data structure 700 may includeone or more resource element blocks that each comprise one or moreresource elements into which a downlink frequency bandwidth 703 isdivided. For example, in example data structure 700, slot 0 702 containsseven separate resource element blocks: resource element blocks 705,706, 707, 712, 714, 716, and 726. Furthermore, each of the resourceelement blocks of data structure 700 may span a single slot or bothslots. For example, again referencing the resource elements of slot 0702, resource element blocks 706, 707, 712, and 714 span one slot (slot0 702), whereas resource element blocks 705, 716, and 726 span bothslots of the subframe (slot 0 702 and slot 1 704). In an aspect, theresource element blocks of example data structure 700 that span one slotmay correspond to a Quick LTE channel of the present disclosure having aone-slot TTI, which may include a QEPDCCH (control channel) or a QPDSCH(data channel). Alternatively, the resource element blocks that spanboth subframes may correspond to a PDSCH (legacy LTE data channel),which may be granted to a particular UE by a PDCCH (e.g., in a legacycontrol region 721), a QPDCCH (shown in data structure 700 as comprisingone or more resource elements of symbol number 0 of slot 0 702), or aEPDCCH (e.g., in resource element block 705). In addition, a resourceelement block that spans both subframes may correspond to an EPDCCH(legacy LTE control channel), such as resource element block 705.

In an additional aspect, each of the one or more resource element blocksmay comprise a control channel region or a data channel region. Forexample, resource element blocks associated with a QPDCCH (e.g., locatedin symbol 0 of slot 0 702), a QEPDCCH (e.g., resource element blocks 706and 718), an EPDCCH (e.g., resource element block 705), or a PDCCH(e.g., located within legacy control region 721) may each correspond tocontrol channel regions. Alternatively, resource element blocksassociated with a PDSCH (e.g., resource element block 716) or a QPDSCH(e.g., resource element blocks 712, 714, and 724) may correspond to datachannel regions.

In addition, the one or more control channel regions of the datastructure 700 may include one or more resource grants for one or moreUEs served by one or shared downlink data channels. These downlink datachannels may include a QPDSCH spanning a single slot of the subframeand/or a PDSCH spanning both slots of the subframe.

In an aspect, one or more of the control channel regions of the datastructure 700 may correspond to a control channel that spans a singleslot of the subframe (e.g., one of slot 0 702 or slot 1 704). Such asingle-slot control channel of the present disclosure may be referred toherein as QEPDCCH, which may have similar aspects to those of the legacyEPDCCH. However, unlike the EPDCCH, which spans both slots of a subframe(see resource element block 705), the QEPDCCH spans a single slot of thesubframe (see resource element blocks 706 and 718). In an aspect, theQEPDCCH may utilize the same or similar enhanced control channelelements (ECCE) resource elements as legacy EPDCCH, although resourceelements may be added relative to the legacy EPDCCH to compensate forthe shorter QEPDCCH timeframe. In other words, the aggregation level ofthe QEPDCCH may be increased relative to the legacy EPDCCH (e.g., by afactor of two) to maintain similar coverage.

Furthermore, control channel regions of data structure 700 allocated tothe QEPDCCH may include one or more uplink or downlink grants. Forexample, resource element block 718, which is allocated to the QEPDCCH,includes both a downlink resource grant 720 for a UE 3 (for single-slotresource element block 724) and an uplink resource grant 722 for a UE 4(for a subsequent subframe). QEPDCCH resource element block 706, on theother hand, does not contain an uplink resource grant, but contains twodownlink resource grants: downlink resource grant 708 for UE 1 (forsingle-slot resource element block 712) and downlink resource grant 710for UE 2 (for single-slot resource element block 714).

In an additional aspect of the present disclosure, a control channelregion of data structure 700 may include a downlink channel grant for adata channel region resource element block that spans both slot 0 702and slot 1 704 of the subframe. For example, resource element block 705carries EPDCCH control data that may include a downlink grant for alegacy PDSCH channel data channel region that spans both slots, such asresource element block 716. Alternatively, the data resource grant forresource element block 716 may be carried by a PDCCH of legacy controlregion 721, which may contain resource elements for a legacy LTE controlchannel (e.g., PDCCH). In an aspect, although shown as spanning a singleinitial symbol 0 of the subframe, legacy control region 721 mayalternatively span a plurality of initial symbols of the subframe.

Moreover, although the initial symbol (or symbols) of the subframe maycontain the legacy control region 721, the symbol may also containresource elements for a QPDCCH channel of the present disclosure.Accordingly, the QPDCCH may utilize the control channel element (CCE)structure of the legacy PDCCH and may be fully multiplexed with otherlegacy control channels of legacy control region 721. Furthermore, theQPDCCH may include one or more downlink resource grants for resourceelement blocks spanning either one or both slots of the subframe. Inother words, the QPDCCH may include downlink resource grants for QPDSCHresource element blocks (spanning a single slot of the subframe, 0.5 msTTI) or PDSCH resource element blocks (spanning both slots of thesubframe, 1 ms TTI). For example, the QPDCCH may include a downlinkresource grant for resource element block 707, which includes a QPDSCHdownlink transmission allocation for a UE 5. Likewise, the QPDCCH mayinclude a downlink resource grant for resource element block 726, whichincludes a PDSCH downlink transmission allocation for a UE 7. In anadditional aspect, as the QPDCCH may include downlink grants forresource element blocks for the single-slot QPDSCH or for thefull-subframe PDCCH, the QPDCCH may include a downlink control indicator(DCI) that specifies whether a downlink channel grant is for a singleslot or for a full subframe. Furthermore, though not explicitly shown indata structure 700, like the legacy LTE PDCCH, the QPDCCH may includeuplink grants in addition to downlink grants.

Furthermore, the resource element blocks that comprise data channelregions may correspond to resource element allocations for downlinktransmission of user data to one or more UEs. In an aspect, these datachannel regions may include resource element blocks allocated todownlink channels that transmit the user data over a single-slot (e.g.,QPDSCH resource element blocks 707, 712, 714, and 724) or downlinkchannels that transmit the user data over both slots of the subframe(e.g., PDSCH resource element blocks 716 and 726.

Therefore, as illustrated in FIG. 7, data structure 700 includes a QuickLTE downlink resource element allocation structure for some resourceelement blocks that may implement a slot-based allocation scheme,thereby shortening (e.g. halving) the TTI relative tofull-subframe-based legacy LTE downlink resource element allocationschemes. By utilizing this Quick LTE downlink resource elementallocation structure, over-the-air latency may be significantly reduced(e.g., by a factor of two). Accordingly, a round-trip time (RTT) of aHARQ process using the Quick LTE structure may be reduced to 4 ms fromthe 8ms RTT of the legacy LTE RTT.

In an additional feature, data structure 700 may allocate resourceelements in a downlink subframe for UEs that utilize one or both of (a)the Quick LTE channels of the present disclosure that span a single slotand may have a 0.5 ms TTI (e.g., QPDCCH, QEPDCCH, QPDSCH) and (b) legacyLTE channels that span the entire subframe and may therefore have a 1 msTTI. In addition, because data structure 700 mirrors the general 1 mssubframe structure of legacy LTE, introducing the Quick LTE structuredoes not alter basic communication operations, such as, but not limitedto, cell search procedures, system information block reading, randomaccess channel (RACH) procedures (with media access channel (MAC)enhancements for contention-based RACH, paging, and idle modeprocedures. Furthermore, UEs may easily indicate whether they supportthe Quick LTE communication during connection setup (e.g., via adedicated information element or message), and in response, a networkentity (e.g., an eNB) may provide the configuration parameters for theQuick LTE downlink and uplink channels.

Moreover, in some examples, cell-specific reference signal (CRS)-baseddemodulation may be utilized for the slot-based resource elementallocation of the Quick LTE structure to minimize its specification andimplementation impact, as CRS-based demodulation is widely used inlegacy LTE systems. Alternatively, demodulation reference signal(DMRS)-based demodulation may be utilized. DMRS-based demodulation canallow for sufficient resources to be used for channel estimation foreach slot of a subframe. For example, DMRS allows for increased density,as a UE-specific reference signal (VERS) pattern defined forTime-Division Duplex (TDD) Downlink Pilot Time Slot (DwPTS) can bereused for both slots of a subframe. In addition, DMRS-baseddemodulation allows for UE combining across consecutive assignments. Asboth CRS and DMRS-based demodulation are utilized by legacy LTE systems,utilizing these demodulation schemes for Quick LTE communication allowsfor further increased compatibility.

In addition, by reducing transmission from one subframe of legacy LTE toone slot of the Quick LTE structure of the present disclosure, theamount of resources for data transmission is effectively reduced byhalf. As such, to facilitate transmission of the same amount of datausing the reduced resources available in a single slot, an increase incode rate (e.g., a doubled code rate) may be required. Alternatively oradditionally, a number of resource blocks (RBs) (or resource elements)for a resource element block assignment may be increased (e.g.,doubled). Therefore, where a resource element block assignment iscompressed in time (e.g., changed from a subframe-based TTI to a singleslot TTI), the number of resource RBs of the resource element blockassignment may expanded. In addition, a two-resource-block minimumassignment may be mandated such that a similar code rate and transportblock size can be maintained regardless of TTI size. However, where aone-RB minimum assignment is in place, a transport block size may bescaled by a factor of two. Alternatively, separate mapping rules may beprovided for subframe-level (i.e., legacy LTE) assignments versusslot-level assignments (i.e., Quick LTE) with respect to transport blocksize, modulation and coding scheme (MCS), and resource block size. Inaddition, slot 0 and slot 1 may have a different mapping or scaling.

In addition, no channel state information (CSI) feedback change isneeded relative to legacy LTE for CRS-based demodulation when Quick LTEslot-based resource element block assignment structures are utilizedbecause the same feedback is provided regardless of transmission lengthor TTI. However, when generating the data structure 700, an eNB mayaccount for the total number of available resource elements to perform amapping operation that includes selecting resource block assignments,MCS selection, and the like.

Moreover, in some examples, the same subframe-level channel stateinformation reference signal (CSI-RS) and interference measurementresource (IMR) may be used regardless of the TTI of a resource elementblock (i.e., same for both Quick LTE and legacy LTE assignments).Alternatively, an eNB may generate a configuration whereby a CSI-RSand/or IMR are provided on a per-slot basis to provide greatergranularity for slot-level assignments of Quick LTE.

Therefore, the data structure 700 of the present disclosure reducesover-the-air LTE latency by reducing the TTI interval of downlinkchannels while maintaining backward compatibility and coexistence withchannels that utilize legacy LTE scheduling structures.

FIG. 8 is a block diagram containing a plurality of sub-components of adownlink scheduling component 602 (see FIG. 6), which may be implementedby a network entity (e.g., an eNodeB) for scheduling expedited downlinktransmissions (e.g., on a per-slot basis) of control information and/oruser data to one or more UEs, for example, to reduce latency in an LTEsystem. Downlink scheduling component 602 may include a data structuregenerating component 802, which may be configured to generate a datastructure that manages downlink resource allocation for transmission ofcontrol information 810 and/or user data 806 to one or more UEs. In anaspect, the generated data structure may include any data structuredescribed in the present disclosure, such as data structure 700 of FIG.7.

In an aspect, data structure generating component 802 may be configuredto utilize a downlink scheduling algorithm 804, which may be configuredto perform scheduling of user data for transmission 806 in the datastructure according to the methodologies and structures defined herein.For example, in some examples, downlink scheduling algorithm maymaintain one or more look-up tables or maps that define transport blocksize, MCS, number of resource blocks, etc. for resource element blockallocations having a single-slot TTI and for resource element blockallocations having full-subframe TTIs. In addition, the data structuregenerating component 802 may include or otherwise obtain or identify oneor more delivery constraints 808 associated with the user data fortransmission 806 and/or one or more UEs to which the user data fortransmission 806 is to be transmitted. In an aspect, such deliveryconstraints 808 may include downlink channel frequency bandwidthconstraints (e.g., available resource blocks), QoS constraints, latencyrequirements, radio conditions, such as may be reported via a CSImessage, an amount of data in a transmit queue for a UE, an amount ofdata for retransmission, e.g., due to operation of one or more HARQprocesses, or any other constraint imposed by a particular UE,application, associated data, or network operation.

The data structure generating component 802 may utilize the downlinkscheduling algorithm 804, which may take at least the deliveryconstraints 808 and the user data for transmission 806 as inputparameters, to generate the data structure to optimize scheduling of theuser data for transmission 806 to the one or more UEs, for example, suchthat the data is transmitted with a TTI of one slot or a TTI of onesubframe, depending on the particular resource element block to beassigned.

FIG. 9 illustrates an example method 900 of the present disclosure,which may be performed by a network entity (e.g., an eNodeB) thatsupports Quick LTE and/or legacy LTE or a component of the networkentity, such as, but not limited to, downlink scheduling component 602of FIG. 6 and FIG. 8. For example, in an aspect, at block 902, method900 may include obtaining, at a network entity, user data fortransmission to one or more UEs on a downlink channel. In some examples,the downlink channel may comprise one or both of a QPDSCH and a PDSCH.For example, in an aspect, an eNodeB may receive one or more data flows,for instance, from one or more network entities (e.g., another eNodeB,an MME, core network entity, or any other network entity) and maymaintain or establish one or more radio bearers to one or more UEs totransmit user data from the data flows to the one or more UEs.

Furthermore, at block 904, method 900 may include determining one ormore delivery constraints associated with at least one of the data andthe one or more UEs. In an aspect, such delivery constraints may includedownlink channel frequency bandwidth constraints (e.g., availableresource blocks), Quality of Service (QoS) constraints, latencyrequirements, radio conditions, such as may be reported via a channelstate information (CSI) message, an amount of data in a transmit queuefor a UE, an amount of data for retransmission, e.g., due to operationof one or more HARQ processes, or any other constraint imposed by aparticular UE, application, associated data, or network operation.

In addition, at block 906, method 900 may include generating, based onthe user data for transmission and the one or more delivery constraints,a downlink subframe data structure for allocating downlink channelresources for transmission of the data. In an aspect, the data structuremay include any data structure described in the present disclosure, suchas data structure 700 of FIG. 7. As such, the downlink subframe datastructure at block 906 may include a downlink subframe comprising twoslots and including one or more quick downlink channels having asingle-slot transmission time interval. In an aspect, the quick downlinkchannels may correspond to the Quick LTE channels described in thepresent disclosure. In addition, the data structure may include one ormore resource element blocks each comprising one or more resourceelements into which a frequency bandwidth is divided within one or bothof the two slots. Additionally, each of the one or more resource elementblocks may include a control channel region or a data channel region.Moreover, the data structure may include one or more resource grants,located within one or more control channel regions, for one or more userequipment served by the one or more quick downlink channels. Optionally(as indicated by the dashed lines), at block 908, method 900 may includetransmitting the generated data structure, for example, to one or moreUEs.

In addition, although not explicitly shown in FIG. 9, method 900 mayinclude one or more alternative or additional features. For example,method 900 may include increasing an aggregation level associated withthe one or more quick downlink channels, for example, relative tochannels having a full-subframe TTI. In addition, method 900 may includedoubling a transport block size associated with the user data where theone or more resource element blocks of the quick downlink channelcorresponding to the user data comprises a single resource block.

Furthermore, additional features of method 900 may be related to a HARQprocess that may be associated with Quick LTE communications and mayhave a HARQ response time of about 4 ms or any other time less than thatof a legacy LTE HARQ response. For example, method 900 may furthercomprise maintaining a HARQ process with an expedited retransmissiontime, wherein the expedited retransmission time is about 4 ms.

FIG. 10 is a conceptual data flow diagram 1000 illustrating the dataflow between different modules/means/components in an exemplaryapparatus 1002. The apparatus 1002 may be an access point (such as aneNodeB (eNB)), which may include access point 105 of FIG. 1, macro eNB204 or low power class eNB 208 of FIG. 2, or eNB 610 of FIG. 6. Theapparatus includes a receiving module 1004, downlink schedulingcomponent 602 (and its related data structure generating component 802(see, e.g., FIG. 8)), and a transmission module 1006 that is configuredto transmit at least a data structure (e.g., data structure 700 of FIG.7) and/or user data for transmission 806 to one or more UEs 115.

The receiving module 1004, downlink scheduling component 602 (and thesubcomponents thereof in FIG. 6), or the transmission module 1006 mayperform one or more aspects of the aforementioned method 900 of FIG. 9.For instance, receiving module 1004 may be configured to receive userdata 1010 from one or more other network entities 1008 in one or moredata flows. The receiving module 1004 may forward the user data 1010 tothe downlink scheduling component 602, and as such, the downlinkscheduling component 602 may obtain the forwarded user data 1012. Thedownlink scheduling component 602 may determine one or more deliveryconstraints associated with at least one of the user data 1012 and theone or more UEs 115 and may generate a downlink subframe data structurefor allocating downlink channel resources for transmission of the userdata 1012. The downlink scheduling component 602 may send the downlinksubframe data structure and the user data (together, 1014) to thetransmission module 1006. The transmission module 1006 may be configuredto transmit at least the downlink subframe data structure and the userdata (together, 1016) to the one or more UEs 115.

In addition, the apparatus 1002 may include additional modules thatperform each of the steps of method 900 of FIG. 9. As such, each step ofmethod 900 may be additionally or alternatively performed by anadditional module and the apparatus 1002 may include one or more ofthose additional modules. The modules may be one or more hardwarecomponents specifically configured to carry out the statedprocesses/algorithm, implemented by a processor configured to performthe stated processes/algorithm, stored within a computer-readable mediumfor implementation by a processor, or some combination thereof.

FIG. 11 is a diagram 1100 illustrating an example of a hardwareimplementation for an apparatus 1002′ employing a processing system1114. Like apparatus 1002 of FIG. 10, apparatus 1002′ and/or processingsystem 1114 may be an access point (such as an eNodeB (eNB)), which mayinclude access point 105 of FIG. 1, macro eNB 204 or low power class eNB208 of FIG. 2, or eNB 610 of FIG. 6. The processing system 1114 may beimplemented with a bus architecture, represented generally by the bus1124. The bus 1124 may include any number of interconnecting buses andbridges depending on the specific application of the processing system1114 and the overall design constraints. The bus 1124 links togethervarious circuits including one or more processors and/or hardwaremodules, represented by the processor 1104, the downlink schedulingcomponent 602 and its related data structure generating component 802(see, e.g., FIG. 8), and the computer-readable medium 1106. The bus 1124may also link various other circuits such as timing sources,peripherals, voltage regulators, and power management circuits, whichare well known in the art, and therefore, will not be described anyfurther.

The processing system 1114 may be coupled to a transceiver 1110, which,in some examples, may include receiving module 1004 and transmissionmodule 1006 of FIG. 10. The transceiver 1110 is coupled to one or moreantennas 1120. The transceiver 1110 provides a means for communicatingwith various other apparatus over a transmission medium. In addition,the transceiver 1110 may be configured to transmit a data structureand/or user data for transmission to one or more UEs. The processingsystem 1114 includes a processor 1104 coupled to a computer-readablemedium 1106. The processor 1104 is responsible for general processing,including the execution of software stored on the computer-readablemedium 1106. The software, when executed by the processor 1104, causesthe processing system 1114 to perform the various functions describedsupra for any particular apparatus. The computer-readable medium 1106may also be used for storing data that is manipulated by the processor1104 when executing software. The processing system further includes atleast one of downlink scheduling component 602 and its related datastructure generating component 802 (see, e.g., FIG. 8). Themodules/components may be software modules running in the processor1104, resident/stored in the computer-readable medium 1106, one or morehardware modules coupled to the processor 1104, or some combinationthereof. The processing system 1114 may be a component of the eNB 610and may include the memory 676 and/or at least one of the TX processor616, the RX processor 670, and the controller/processor 675.

In one configuration, the apparatus 1002′ for wireless communicationincludes means for obtaining user data for transmission 806 to one ormore UEs on a downlink channel; means for determining one or moredelivery constraints 808 associated with at least one of the data andthe one or more UEs; and means for generating, based on the user datafor transmission 806 and the one or more delivery constraints 808, adownlink subframe data structure for allocating downlink channelresources for transmission of the user data for transmission 806. Theaforementioned means may be one or more of the aforementioned modules ofthe apparatus 1002 and/or the processing system 1114 of the apparatus1002′ configured to perform the functions recited by the aforementionedmeans. As described supra, the processing system 1114 may include the TXProcessor 616, the RX Processor 670, and the controller/processor 675.As such, in one configuration, the aforementioned means may be the TXProcessor 616, the RX Processor 670, and the controller/processor 675configured to perform the functions recited by the aforementioned means.

Furthermore, like method 900, which may be performed by an example eNBof the present disclosure, one or more UEs (e.g., UE 115 of FIG. 1 or UE115 of FIG. 2) may perform methods related to the LTE data structurespresented herein. For instance, FIG. 12 illustrates an example method1200 of the present disclosure, which may be performed by a UE (e.g., UE115 of FIGS. 1, 2 and 10) that supports Quick LTE and/or legacy LTE. Inan aspect, aspects of method 1200 may be performed by downlinkmanagement component 661 (see FIGS. 1, 2, 6) and/or any other component(e.g., controller/processor 659 of FIG. 6) of a UE.

In an aspect, method 1200 may include receiving, at a UE, controlinformation located at one or more resource element positions in acontrol channel region of a downlink subframe or slot at block 1202.This control channel region may include at least a portion of a downlinkdata structure (see data structure 700 of FIG. 7) defined by one or moreresource elements or resource element blocks. In an aspect, block 1202may be performed by receiving module 1304 of FIG. 13 or transceiver 1410of FIG. 14.

In addition, method 1200 may include, at block 1204, performing a checkon the control channel region received at each of the one or moreresource element positions to determine if the control information isfor the UE. In an aspect, this check may include a cyclic redundancycheck (CRC). Furthermore, in some examples, block 1204 may be performedby control channel region checking component 1306 of FIG. 13.

In addition, at block 1206, method 1200 may include determining, wherethe check passes, a position of a data channel region and a TTI lengthof the data channel region based on the control information. This datachannel region may include at least a portion of a downlink datastructure (see data structure 700 of FIG. 7) defined by one or moreresource elements or resource element blocks. In some examples, block1206 may be performed by data channel region determining component 1308

Moreover, at block 1208, method 1200 may include receiving, at thedetermined position, downlink data in the data channel region. In someexamples, block 1208 may be performed by receiving module 1304 of FIG.13 or transceiver 1410 of FIG. 14.

In addition, it is understood that the specific order or hierarchy ofsteps in the methods disclosed in FIGS. 9 and 13 is an illustration ofexemplary approaches. Based upon design preferences, it is understoodthat the specific order or hierarchy of steps in the processes may berearranged. Further, some steps may be combined or omitted. Theaccompanying method claims present elements of the various steps in asample order, and are not meant to be limited to the specific order orhierarchy presented.

FIG. 13 is a conceptual data flow diagram 1300 illustrating the dataflow between different modules/means/components in an exemplaryapparatus 1302, which may be a UE (e.g., UE 115 of FIGS. 1, 2, and 10).In an aspect, the apparatus 1302 includes a receiving module 1304 thatis configured to receive data 1316, which may include a data structure700 of FIG. 7 and associated control data received via a control channeland/or downlink data via a data channel. Such data 1316 may betransmitted to apparatus 1302, for example, by a network entity 1303,which may include, but is not limited to, access point 105 of FIG. 1,macro eNB 204 or low power class eNB 208 of FIG. 2, or eNB 610 of FIG.6, any of which may include downlink scheduling component 602 and itsrelated data structure generating component 802 (see, e.g., FIG. 8). Forinstance, receiving module 1304 may be configured to receive controlinformation located at one or more resource element positions in acontrol channel region of a downlink subframe or slot as defined by areceived data structure (data structure 700 of FIG. 7). In addition,receiving module 1304 may be configured to receive user data in a datachannel region of the received data structure, where the user data isreceived at a determined position in the received data structurecorresponding to a particular frequency band. The receiving module 1304may send the received data 1318 to the downlink management component661.

In addition, apparatus 1302 may contain a downlink management component661 (see FIGS. 1 and 2) and a plurality of sub-components thereof, whichmay be implemented by apparatus 1302 to decode and process data (e.g.,received data 1318) and operate using the data structure 700 of FIG. 7,for example, to reduce latency in an LTE system. Downlink managementcomponent 611 may include a control region checking component 1306,which may be configured to perform a check on the control channel regionreceived at each of one or more resource element positions in thereceived data structure to determine if the control information is forthe apparatus 1302. In an aspect, this check may include a CRC.

In addition, downlink management component 661 may include a datachannel region determining component 1308, which may be configured todetermine, where the check performed by control region checkingcomponent 1306 passes, a position of a data channel region 1310 and aTTI length of the data channel region 1312 based on the controlinformation included in the received data structure. This data channelregion may include at least a portion of a downlink data structure (seedata structure 700 of FIG. 7) defined by one or more resource elementsor resource element blocks. In an aspect, the downlink managementcomponent 661 may be configured to send the position of the data channelregion 1310 and the TTI length of data channel region 1312 to thereceiving module 1304, which may utilize this information to receivedata 1316 transmitted by access point 105.

The apparatus may include additional modules that perform each of thesteps of the algorithm in the aforementioned flow chart of FIG. 12. Assuch, each step in the aforementioned flow charts of FIG. 12 may beperformed by a module and the apparatus may include one or more of thosemodules. The modules may be one or more hardware components specificallyconfigured to carry out the stated processes/algorithm, implemented by aprocessor configured to perform the stated processes/algorithm, storedwithin a computer-readable medium for implementation by a processor, orsome combination thereof.

FIG. 14 is a diagram 1400 illustrating an example of a hardwareimplementation for an apparatus 1302′ employing a processing system1414. Like apparatus 1302 of FIG. 13, apparatus 1302′ and/or processingsystem 1414 may be a UE (e.g., UE 115 of FIGS. 1, 2, and 10). Theprocessing system 1414 may be implemented with a bus architecture,represented generally by the bus 1424. The bus 1424 may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system 1414 and the overall designconstraints. The bus 1424 links together various circuits including oneor more processors and/or hardware modules, represented by the processor1404, the downlink management component 611 (see, e.g., FIG. 8), and thecomputer-readable medium 1406. The bus 1424 may also link various othercircuits such as timing sources, peripherals, voltage regulators, andpower management circuits, which are well known in the art, andtherefore, will not be described any further.

The processing system 1414 may be coupled to a transceiver 1410, which,in some examples, may include receiving module 1304 of FIG. 13. Thetransceiver 1410 is coupled to one or more antennas 1420. Thetransceiver 1410 provides a means for communicating with various otherapparatus (e.g., access point 105 of FIGS. 1 and 13) over a transmissionmedium. In addition, the transceiver 1410 may be configured to receive adata structure and/or user data. The processing system 1414 includes aprocessor 1404 coupled to a computer-readable medium 1406. The processor1404 is responsible for general processing, including the execution ofsoftware stored on the computer-readable medium 1406. The software, whenexecuted by the processor 1404, causes the processing system 1414 toperform the various functions described supra for any particularapparatus. The computer-readable medium 1406 may also be used forstoring data that is manipulated by the processor 1404 when executingsoftware. The processing system further includes downlink managementcomponent 611 and its related subcomponents (see, e.g., FIG. 13). Themodules/components may be software modules running in the processor1404, resident/stored in the computer-readable medium 1406, one or morehardware modules coupled to the processor 1404, or some combinationthereof. The processing system 1414 may be a component of the UE 650 andmay include the memory 660 and/or at least one of the TX processor 668,the RX processor 656, and the controller/processor 659 of FIG. 6.

In one configuration, the apparatus 1302′ for wireless communicationincludes means for receiving, at a UE, control information located atone or more resource element positions in a control channel region of adownlink; means for performing a check on the control channel regionreceived at each of the one or more resource element positions todetermine if the control information is for the UE; means fordetermining, where the check passes, a position of a data channel regionand a TTI length of the data channel region based on the controlinformation; and means for receiving, at the determined position,downlink data in the data channel region.

The aforementioned means may be one or more of the aforementionedmodules of the apparatus 1302′ and/or the processing system 1114configured to perform the functions recited by the aforementioned means.As described supra, the processing system 1114 may include the TXProcessor 616, the RX Processor 670, and the controller/processor 675.As such, in one configuration, the aforementioned means may be the TXProcessor 616, the RX Processor 670, and the controller/processor 675,or any other component of the present disclosure configured to performthe functions recited by the aforementioned means.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed as a means plus functionunless the element is expressly recited using the phrase “means for.”

What is claimed is:
 1. A method for managing user equipment (UE)communications in a wireless communications system, comprising:receiving, at the UE, control information located at one or moreresource element positions in a control channel region of a downlinksubframe or a slot of the downlink subframe; performing a check on thecontrol channel region received at each of the one or more resourceelement positions to determine whether corresponding control informationis for the UE; determining, where the check indicates the correspondingcontrol information is for the UE, a position of a data channel regionand a transmission time interval (TTI) length of the data channel regionbased on the corresponding control information; and receiving, at thedetermined position, downlink data in the data channel region.
 2. Themethod of claim 1, wherein the downlink subframe includes one or morequick downlink channels having a single-slot TTI.
 3. The method of claim2, wherein the downlink subframe further includes one or more legacydownlink channels having a two-slot TTI.
 4. The method of claim 1,wherein the control channel region comprises a legacy control channelregion that includes all resource elements of a symbol of at least oneof two slots of the downlink subframe.
 5. The method of claim 1, whereinthe control channel region spans one slot of the downlink subframe andincludes the control information indicating one or more downlinkresource grants for one or more quick downlink channels in the datachannel region.
 6. The method of claim 1, wherein the control channelregion comprises an uplink resource grant for the UE.
 7. The method ofclaim 1, wherein the control channel region spans two slots of thedownlink subframe and the control information includes a downlinkresource grant corresponding to the data channel region spanning the twoslots.
 8. The method of claim 1, wherein the downlink subframecomprises: two slots and includes one or more quick downlink channelshaving a single-slot TTI; and one or more resource element blocks eachcomprising one or more resource elements into which a frequencybandwidth is divided within one or both of the two slots, wherein eachof the one or more resource element blocks comprises the control channelregion or the data channel region corresponding to the one or more quickdownlink channels, and wherein at least the control channel region ismultiplexed, within at least one symbol, with a legacy control channelregion.
 9. An apparatus for managing user equipment (UE) communicationsin a wireless communications system, comprising: a processor; and amemory coupled to the processor, wherein the memory storesprocessor-executable instructions, that when executed by the processor,cause the processor to: receive, at the UE, control information locatedat one or more resource element positions in a control channel region ofa downlink subframe or a slot of the downlink subframe; perform a checkon the control channel region received at each of the one or moreresource element positions to determine whether corresponding controlinformation is for the UE; determine, where the check indicates thecorresponding control information is for the UE, a position of a datachannel region and a transmission time interval (TTI) length of the datachannel region based on the corresponding control information; andreceive, at the determined position, downlink data in the data channelregion.
 10. The apparatus of claim 9, wherein the downlink subframeincludes one or more quick downlink channels having a single-slot TTI.11. The apparatus of claim 10, wherein the downlink subframe furtherincludes one or more legacy downlink channels having a two-slot TTI. 12.The apparatus of claim 9, wherein the control channel region comprises alegacy control channel region that includes all resource elements of asymbol of at least one of two slots of the downlink subframe.
 13. Theapparatus of claim 9, wherein the control channel region spans one slotof the downlink subframe and includes the control information indicatingone or more downlink resource grants for one or more quick downlinkchannels in the data channel region.
 14. The apparatus of claim 9,wherein the control channel region comprises an uplink resource grantfor the UE.
 15. The apparatus of claim 9, wherein the control channelregion spans two slots of the downlink subframe and the controlinformation includes a downlink resource grant corresponding to the datachannel region spanning the two slots.
 16. The apparatus of claim 9,wherein the downlink subframe comprises: two slots and includes one ormore quick downlink channels having a single-slot TTI; and one or moreresource element blocks each comprising one or more resource elementsinto which a frequency bandwidth is divided within one or both of thetwo slots, wherein each of the one or more resource element blockscomprises the control channel region or the data channel regioncorresponding to the one or more quick downlink channels, and wherein atleast the control channel region is multiplexed, within at least onesymbol, with a legacy control channel region.
 17. An apparatus formanaging user equipment (UE) communications in a wireless communicationssystem, comprising: means for receiving, at the UE, control informationlocated at one or more resource element positions in a control channelregion of a downlink subframe or a slot of the downlink subframe; meansfor performing a check on the control channel region received at each ofthe one or more resource element positions to determine whethercorresponding control information is for the UE; means for determining,where the check indicates the corresponding control information is forthe UE, a position of a data channel region and a transmission timeinterval (TTI) length of the data channel region based on thecorresponding control information; and means for receiving, at thedetermined position, downlink data in the data channel region.
 18. Theapparatus of claim 17, wherein the downlink subframe includes one ormore quick downlink channels having a single-slot TTI and one or morelegacy downlink channels having a two-slot TTI.
 19. The apparatus ofclaim 17, wherein the control channel region comprises a legacy controlchannel region that includes all resource elements of a symbol of atleast one of two slots of the downlink subframe.
 20. The apparatus ofclaim 17, wherein the control channel region spans one slot of thedownlink subframe and includes the control information indicating one ormore downlink resource grants for one or more quick downlink channels inthe data channel region.
 21. The apparatus of claim 17, wherein thecontrol channel region comprises an uplink resource grant for the UE.22. The apparatus of claim 17, wherein the control channel region spanstwo slots of the downlink subframe and the control information includesa downlink resource grant corresponding to the data channel regionspanning the two slots.
 23. The apparatus of claim 17, wherein thedownlink subframe comprises: two slots and includes one or more quickdownlink channels having a single-slot TTI; and one or more resourceelement blocks each comprising one or more resource elements into whicha frequency bandwidth is divided within one or both of the two slots,wherein each of the one or more resource element blocks comprises thecontrol channel region or the data channel region corresponding to theone or more quick downlink channels, and wherein at least the controlchannel region is multiplexed, within at least one symbol, with a legacycontrol channel region.
 24. A non-transitory computer-readable storagemedium comprising computer-executable code for managing user equipmentcommunications in a wireless communications system, the code comprising:code for receiving, at the UE, control information located at one ormore resource element positions in a control channel region of adownlink subframe or a slot of the downlink subframe; code forperforming a check on the control channel region received at each of theone or more resource element positions to determine whethercorresponding control information is for the UE; code for determining,where the check indicates the corresponding control information is forthe UE, a position of a data channel region and a transmission timeinterval (TTI) length of the data channel region based on thecorresponding control information; and code for receiving, at thedetermined position, downlink data in the data channel region.
 25. Thenon-transitory computer-readable storage medium of claim 24, wherein thedownlink subframe includes one or more quick downlink channels having asingle-slot TTI and one or more legacy downlink channels having atwo-slot TTI.
 26. The non-transitory computer-readable storage medium ofclaim 24, wherein the control channel region comprises a legacy controlchannel region that includes all resource elements of a symbol of atleast one of two slots of the downlink subframe.
 27. The non-transitorycomputer-readable storage medium of claim 24, wherein the controlchannel region spans one slot of the downlink subframe and includes thecontrol information indicating one or more downlink resource grants forone or more quick downlink channels in the data channel region.
 28. Thenon-transitory computer-readable storage medium of claim 24, wherein thecontrol channel region comprises an uplink resource grant for the UE.29. The non-transitory computer-readable storage medium of claim 24,wherein the control channel region spans two slots of the downlinksubframe and the control information includes a downlink resource grantcorresponding to the data channel region spanning the two slots.
 30. Thenon-transitory computer-readable storage medium of claim 24, wherein thedownlink subframe comprises: two slots and includes one or more quickdownlink channels having a single-slot TTI; and one or more resourceelement blocks each comprising one or more resource elements into whicha frequency bandwidth is divided within one or both of the two slots,wherein each of the one or more resource element blocks comprises thecontrol channel region or the data channel region corresponding to theone or more quick downlink channels, and wherein at least the controlchannel region is multiplexed, within at least one symbol, with a legacycontrol channel region. 030284.15357